In the field of digital signal processing, there are many applications where two filters cooperate unidirectionally or bidirectionally. In a unidirectional relationship, one filter may receive the output of the other and perform operations on this. As one example, a real-to-imaginary conversion of a frequency-domain representation of a signal may proceed as a frequency-to-time synthesis step followed by a time-to-frequency analysis. Since a transform filter by its nature introduces a non-zero delay, arrangements of two or more filters may have a considerable total delay that may in some situations pose an inconvenience. For this and other reasons, alternative solutions have been proposed, including the real-to-imaginary conversion described in the Applicant's U.S. Pat. No. 6,980,933. It would be desirable, however, to propose further alternatives in addition to this approach.
All the figures are schematic and generally only show parts which are necessary in order to elucidate the invention, whereas other parts may be omitted or merely suggested. Unless otherwise indicated, like reference numerals refer to like parts in different figures.